Economics

You can do BA in Economics with either one. None of the above is mandatory.

Maths, statistics, information practice and geography are good options for economics. Economics, education, sociology and history are some good options for political science. You can choose other subjects too.

Both the subjects are good. It actually depends on your area of interest. I believe you are the best person to decide where you should go. Any outsider can never decide this for you. Whatever you do just keep your scorecard excellent. It will always keep you ahead of others. I hope this would suffice. All the best and god bless you.

Yes, every PG courses requires a minimum percentage from UG course. Irrespective of which course you wish to choose.

According to UPSC examination, it has an important role in respect of knowledge and syllabus wise.
But in respect of professional degree, my vote will go for Economics Honors for plan B. If you are not able to clear the UPSC exam, you can start your job and further education for a better career.

Yes, infact BA with journalism is a good option for journalism. Try some university level e-paper like PU PULSE.

You can opt for M.Com with specialisation.

This link has detailed structure of the syllabus. Just go through this and good luck.
https://www.google.co.in/url?sa=t&source=web&rct=j&url=http://studychacha.com/discuss/224732-jnu-m-economics-entrance-exam-syllabus.html&ved=0ahUKEwikvZqjtOLVAhXMOY8KHZ2DApcQFggkMAA&usg=AFQjCNFA1SflMb7znbXWonr76GnAMiGseQ

Hello Junaid,
The date and process of admission for MA economics in Jamia Milia Islamia has already passed. One can only get admission, if they had applied for the admission test before.